EP0003391B1 - Apparatus for bending and tempering glass - Google Patents

Apparatus for bending and tempering glass Download PDF

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Publication number
EP0003391B1
EP0003391B1 EP79300012A EP79300012A EP0003391B1 EP 0003391 B1 EP0003391 B1 EP 0003391B1 EP 79300012 A EP79300012 A EP 79300012A EP 79300012 A EP79300012 A EP 79300012A EP 0003391 B1 EP0003391 B1 EP 0003391B1
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EP
European Patent Office
Prior art keywords
glass
holder
sheet
heated
vacuum
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP79300012A
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German (de)
English (en)
French (fr)
Other versions
EP0003391A1 (en
Inventor
Harold A. Mcmaster
Norman Carl Nitschke
John Stephen Nitschke
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Individual
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Individual
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Publication of EP0003391A1 publication Critical patent/EP0003391A1/en
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B23/00—Re-forming shaped glass
    • C03B23/02—Re-forming glass sheets
    • C03B23/023—Re-forming glass sheets by bending
    • C03B23/035—Re-forming glass sheets by bending using a gas cushion or by changing gas pressure, e.g. by applying vacuum or blowing for supporting the glass while bending
    • C03B23/0352—Re-forming glass sheets by bending using a gas cushion or by changing gas pressure, e.g. by applying vacuum or blowing for supporting the glass while bending by suction or blowing out for providing the deformation force to bend the glass sheet
    • C03B23/0357—Re-forming glass sheets by bending using a gas cushion or by changing gas pressure, e.g. by applying vacuum or blowing for supporting the glass while bending by suction or blowing out for providing the deformation force to bend the glass sheet by suction without blowing, e.g. with vacuum or by venturi effect
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B23/00—Re-forming shaped glass
    • C03B23/02—Re-forming glass sheets
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B23/00—Re-forming shaped glass
    • C03B23/02—Re-forming glass sheets
    • C03B23/023—Re-forming glass sheets by bending
    • C03B23/025—Re-forming glass sheets by bending by gravity
    • C03B23/0252—Re-forming glass sheets by bending by gravity by gravity only, e.g. sagging
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B23/00—Re-forming shaped glass
    • C03B23/02—Re-forming glass sheets
    • C03B23/023—Re-forming glass sheets by bending
    • C03B23/03—Re-forming glass sheets by bending by press-bending between shaping moulds
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B27/00—Tempering or quenching glass products
    • C03B27/04—Tempering or quenching glass products using gas
    • C03B27/0417—Controlling or regulating for flat or bent glass sheets
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B27/00—Tempering or quenching glass products
    • C03B27/04—Tempering or quenching glass products using gas
    • C03B27/044—Tempering or quenching glass products using gas for flat or bent glass sheets being in a horizontal position
    • C03B27/048—Tempering or quenching glass products using gas for flat or bent glass sheets being in a horizontal position on a gas cushion
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B29/00—Reheating glass products for softening or fusing their surfaces; Fire-polishing; Fusing of margins
    • C03B29/04—Reheating glass products for softening or fusing their surfaces; Fire-polishing; Fusing of margins in a continuous way
    • C03B29/06—Reheating glass products for softening or fusing their surfaces; Fire-polishing; Fusing of margins in a continuous way with horizontal displacement of the products
    • C03B29/08—Glass sheets
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B35/00—Transporting of glass products during their manufacture, e.g. hot glass lenses, prisms
    • C03B35/14—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands
    • C03B35/145—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands by top-side transfer or supporting devices, e.g. lifting or conveying using suction
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B35/00—Transporting of glass products during their manufacture, e.g. hot glass lenses, prisms
    • C03B35/14—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands
    • C03B35/16—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands by roller conveyors
    • C03B35/163—Drive means, clutches, gearing or drive speed control means
    • C03B35/164—Drive means, clutches, gearing or drive speed control means electric or electronicsystems therefor, e.g. for automatic control
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B35/00—Transporting of glass products during their manufacture, e.g. hot glass lenses, prisms
    • C03B35/14—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands
    • C03B35/20—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands by gripping tongs or supporting frames
    • C03B35/202—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands by gripping tongs or supporting frames by supporting frames
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B35/00—Transporting of glass products during their manufacture, e.g. hot glass lenses, prisms
    • C03B35/14—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands
    • C03B35/22—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands on a fluid support bed, e.g. on molten metal
    • C03B35/24—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands on a fluid support bed, e.g. on molten metal on a gas support bed
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2225/00—Transporting hot glass sheets during their manufacture
    • C03B2225/02—Means for positioning, aligning or orientating the sheets during their travel, e.g. stops

Definitions

  • This invention relates to apparatus for bending and tempering sheet glass.
  • Bent and tempered glass is used extensively for vehicle side and rear windows to provide good resistance to breakage as well as an aesthetically appealing shape that complements the design of the vehicle.
  • sheet glass In order to perform the bending and tempering, sheet glass must be heated to its deformation point of about 650° to 700°C and then bent to the required shape before being rapidly cooled by an air spray in order to temper the glass. Tempering greatly increases the mechanical strength of the glass and its resistance to breakage as well as causing the glass to break into small relatively dull pieces when broken instead of into large sharp slivers as is the case with untempered glass.
  • Sheet glass is also bent and tempered by heating of planar glass sheets while supported on bending molds including movable sections.
  • the sections of the mold Prior to softening of the glass during heating, the sections of the mold are oriented to accommodate for the glass sheet planarity.
  • the mold sections move relative to each other under the force of gravity acting on the sheet and the mold sections in order to provide bending of the sheet prior to rapid cooling thereof which provides its tempering.
  • Thin glass i.e. on the order of 3 mm, cannot be bent by this apparatus since it does not have sufficient weight to actuate the pivoting of the mold sections until the glass becomes so soft that it overbends.
  • United States Patents 3,269,822; 3,278,287; 3,307,930; and 3,365,285 disclose this type of bending and tempering apparatus.
  • Heating of glass sheets prior to bending and tempering thereof has also been performed on fluid support beds as the glass is conveyed through a furnace.
  • the support bed is inclined slightly with respect to the horizontal so that gravity engages an edge of the glass with a movable frame that provides the impetus for glass movement along the bed.
  • This lack of contact prevents marring and scratching of the soft surfaces of the glass as the glass reaches its deformation temperature.
  • United States Patents 3,497,340; 3,607,187; and 3,607,200 disclose glass bending and tempering apparatus of this type with a fluid support bed.
  • Vacuum forming of heated glass sheets is disclosed by United States Patent 3,778,244 wherein the sheet glass is first heated during conveyance along a roller hearth conveyor. After heating, a lifter with a curved downwardly facing surface has a vacuum applied thereto about the surface to shape the glass. After shaping against the curved surface of the lifter, the vacuum is terminated to drop the glass onto a mold for conveyance to a waiting operator who removes the glass from the mold. Further vacuum forming of the glass to a curved surface of the mold is also disclosed.
  • An object of the present invention is to provide improved apparatus capable of bending and tempering thin glass sheets, i.e. on the order of 3 mm thick, to an accurately controlled shape despite the supple nature of such sheets when heated to a sufficiently high temperature for bending and subsequent tempering.
  • the apparatus includes a heating chamber for providing a heated ambient for heating glass sheets to a sufficiently high temperature to permit tempering thereof; a conveyor for conveying glass sheets generally horizontally through the heating chamber; a holder within the heated ambient and positioned at an elevation above the conveyor and having a downwardly facing surface of a predetermined shape at which a differential gas pressure is applied to a heated sheet of glass received from the conveyor so as to support the glass sheet at an elevation above the conveyor in preparation for bending; a cooling unit located outside the heated ambient for cooling bent glass sheets; a mold with a curved shape for receiving a heated glass sheet from the holder at a position thereunder; and an actuator for moving the mold between the holder and the cooling unit, the invention being characterized in that the mold comprises a ring having an open center, that the ring has at least a substantial portion with a downwardly extending curvature greater than the predetermined shape of the holder surface, that the holder receives the heated glass sheet at tempering temperature and thereafter releases the glass sheet for substantial
  • the holder may be located above the conveyor within the heating chamber that provides the heated ambient and the holder surface may include spaced openings at which a vacuum is drawn in order to apply the differential pressure to a heated glass sheet supported by the holder.
  • the holder may also have a porous construction at the surface thereof so as to prevent marring or scratching of heated sheets of glass upon engagement thereof with the holder and so as to also distribute the vacuum between the spaced openings.
  • a surface cover of the holder may be made of ceramic fibers and have the porous construction which prevents marring or scratching of the heated glass sheets and which also distributes the vacuum between the spaced openings.
  • a support raises and lowers the vacuum holder relative to the conveyor so as to facilitate lifting of the heated glass sheets off the conveyor in preparation for the bending.
  • the conveyor includes horizontally extending rolls and auxiliary lifters movable vertically between the rolls to raise a heated sheet of glass toward the vacuum holder and thereby facilitate lifting of the glass sheet in preparation for the bending.
  • the auxiliary lifters of the latter embodiment may have T shapes including upper crossbars . that engage the glass and lower stems that ' extend downwardly from the crossbars between the conveyor rolls.
  • Each lifter crossbar may also include a woven ceramic cloth cover that engages a heated sheet of glass as the lifter moves upwardly to pick the glass off the conveyor rolls.
  • the apparatus may include a vacuum holder control for providing a greater initial vacuum within the openings to facilitate the initial support of a glass sheet and for subsequently providing a reduced vacuum to support the sheet of glass without deforming the sheet at the openings.
  • a quench unit of the apparatus may include a lower blasthead for blowing gas upwardly to lift the bent sheet upwardly off the ring in order to permit movement of the ring from below the lifted sheet back into the heating chamber.
  • the surface of the holder has a planar shape so as to be capable of supporting a glass sheet of a selected size that is to bend to any desired shape on the ring.
  • Another embodiment includes a holder whose surface has a curved shape so as to allow prebending of the glass sheet on the holder prior to the bending on the ring.
  • the furnace disclosed for heating the glass sheets includes a housing defining the heating chamber thereof, and a roller hearth conveyor for conveying the glass sheets through the heating chamber.
  • An upwardly opening lower housing portion and a fixed roof of the furnace housing cooperate with vertically movable side doors to define the heating chamber.
  • Lower ends of the doors cooperate with the upper ends of the side walls on the lower housing portion to define side slots through which ends of elongated conveyor rolls project outwardly from the heating chamber.
  • Continuous drive loops in the form of either chains or solid steel belts support the ends of the conveyor rolls and are slidably driven over external support surfaces extending alongside the slots to support and frictionally drive the rolls. Upward movement of the side doors permits access to the furnace heating chamber for maintenance and repairs.
  • sensing of the glass position along the conveyor and the operation of a lateral locator accurately position the glass on the holder surface without requiring the conveyor to be stopped prior to the holder operation.
  • One locator disclosed operates during the conveyance upstream from the holder and includes one sensor upstream from the locator and another sensor between the locator and the holder for sensing the longitudinal position of the glass. Both sensors are coupled to the conveyor drive mechanism and the vacuum holder to coordinate their opera- t ion.
  • Another lateral locator disclosed operates after the glass has been lifted by the auxiliary lifters but before it has been initially supported on the holder. A single sensor upstream from this locator is coupled with the conveyor drive mechanism and the auxiliary lifters as well as the vacuum holder to coordinate their operation.
  • one embodiment of the glass bending and tempering apparatus constructed according to the present invention is indicated generally by 20 and includes a furnace 22 as well as a quench unit 24.
  • One end 26 of the furnace 22 receives discrete sheets of glass to be bent and tempered while the other end 28 of the furnace has provisions for bending the glass once it is heated in a manner that is hereinafter described.
  • Quench unit 24 is shown by solid line representation positioned laterally adjacent one side of the furnace end 28 and receives the heated and bent glass to provide tempering thereof in a manner that is likewise hereinafter described. It is also possible for the quench unit 24 to be positioned at the other side of the furnace end 28 or at its longitudinal end as shown by phantom line representation. Quench units can also be provided at any two or all three of these positions to receive heated and bent glass for tempering and thereby increase the system output.
  • the quench unit 24 aligned with the longitudinal direction of the furnace can also be used to temper sheet glass that is not bent.
  • the furnace 22 in which sheet glass is heated includes a housing composed of lower and upper portions 30 and 32, respectively.
  • Lower housing portion 30 is made from refractory blocks 34 mounted on a framework of horizontal and vertical beams 36 defining an upwardly opening U shape.
  • a bottom wall 38 of the lower housing portion 30 is made from a larger refractory block and includes T-shaped retainers 40 for securing heater elements 42.
  • Side walls 44 of the lower housing portion 30 are defined by the refractory blocks 34 extending upwardly from the bottom wall 38 to support upper refractory end blocks 46.
  • Upper housing portion 32 includes a fixed roof 47 and a pair of vertically movable side doors 48 that extend downwardly from the roof in a U shape to cooperate with the upwardly opening U shape of the lower housing portion in defining a heating chamber 50 that provides a heated ambient.
  • Fixed roof 47 also has T-shaped retainers 40 and heater elements 42 secured by the retainers.
  • a horizontal beam 52 is supported at its opposite ends by vertical beams 54 (only one shown in FIGURE 8a) and itself supports horizontal beams 56 that mount nut and bolt connectors 57 for securing the roof 47.
  • a pulley system collectively indicated by 58 counterbalances the weight of each door 48 during movement thereof between its lower closed position shown by solid line representation and its upper open position shown by phantom line representation.
  • Pulley system 58 includes a counterweight 60 (FIGURE 8a) associated with each side door 48 as well as a number of pulleys 62 over which cables 64 are trained so that the counterweight moves up and down with the door upon manual effort applied to the door independently of the other door.
  • the heating chamber 50 In the open positions of the side doors, the heating chamber 50 is accessible for maintenance and repair. In the lower closed positions, the side doors prevent the escape of heat from the heating chamber 50.
  • a conveyor of the apparatus is indicated collectively by reference numeral 66 in FIGURE 8b and includes a plurality of conveyor rolls 68 (see also FIGURE 9) of fused silica particles that are sinter bonded to each other. Ends of each conveyor roll 68 project outwardly through side slots 70 defined between the upper end blocks 46 of the lower housing portion and the lower ends 72 of the vertically movable side doors 48. Heat seals 73 on the blocks 46 and tower door ends 72 seal the slots 70 to prevent the loss of heat from the furnace to the environment and cooperatively define circular openings (not shown) through which the roll ends project.
  • Continuous drive loops 74 in the form of chains or solid steel belts are slidably driven over upwardly facing support surfaces of members 76 that extend alongside the side slots 70 as best seen in FIGURE 9.
  • Each roll end is positioned between upwardly extending projections 78 which have idler rollers 80 (FIGURE 8b) for preventing movement of the rolls along with the drive loops.
  • Nut and bolt supports 82 mount the support surface members 76 on the horizontal beams 36 in a vertically adjustable manner to maintain planarity of the upper sides of all of the rolls 68.
  • Each end of the horizontal beams 36 mounting the support surface members 76 rotatably mounts a pulley 84 (FIGURE 9) over which the associated drive loops 74 are trained.
  • a cross shaft 85 (FIGURE 12) connects the pulleys 84 and a drive mechanism 86 drives these pulleys by a digital drive motor such as the electric stepper motor 88 which drives a chain 90 to pull the drive loops 74 over the support surfaces and thereby frictionally drive the adjacent roll ends.
  • a digital drive motor such as the electric stepper motor 88 which drives a chain 90 to pull the drive loops 74 over the support surfaces and thereby frictionally drive the adjacent roll ends.
  • a vacuum holder 92 of the apparatus is positioned within the furnace heating chamber 50 at the end of the furnace adjacent the quench unit 24 and has a downwardly facing planar surface 94.
  • Vacuum holder 92 is seen in FIGURE 8b as including an upper portion 96 of a downwardly opening U shape and a lower portion 98 of a relatively thick plate-like construction with edge projections 100 received within associated grooves in the upper portion 96 so as to be secured thereto and cooperate therewith in defining a cavity 102.
  • a sheet-like cover 104 made of ceramic fibers, preferably silica, is compressed in a mat that has a porous construction.
  • any suitable high temperature adhesive is used to secure cover 104 on the downwardly facing planar surface 94 of the lower holder portion 98. Aligned openings or holes 106 and 108 through the holder portion 98 and the cover 104 communicate with the cavity 102. A vacuum drawn within the cavity 102 through a duct 110 by a vacuum blower 112 (FIGURE 3) is thereby drawn in the holes 106 and 108 in order to support a heated sheet of glass on the holder above the conveyor rolls-68 shown in FIGURE 8b. Cover 104 prevents marring or scratching of the soft glass surface as the glass sheet is engaged with the holder and, due to its porous construction, distributes the vacuum between the holes.
  • a control or damper 114 of duct 110 is located in its solid line indicated position of FIGURE 3 by an actuator embodied as a cylinder 116.
  • One end of cylinder 116 is pivotally fixed by a pin 118 to a stationary support while a piston rod 119 of the cylinder is secured by a pin 120 to the damper 114.
  • No vacuum reaches the lower holder surface 94 with the damper in this position so that the glass is free to move under the holder.
  • the cylinder 116 is supplied pressurized fluid to retract its rod 119 and to move the damper to its position shown by phantom line representation and indicated at 114'.
  • An opening 121 to the environmental atmosphere through duct 110 is open with the damper in its solid line 114 position and dosed by the damper in its phantom line position 114'.
  • Vacuum is supplied to the lower holder surface 94 to pick up the sheet of glass with the damper in position 114'.
  • the cylinder 116 is supplied pressurized fluid to extend its connecting rod 119 and position the damper in the partially open position with respect to duct opening 121 as shown by phantom line representation and indicated by 114". Only a partial vacuum is drawn in the holder by the blower 112 with the damper in this partially opened position as a result of the atmospheric pressure that can enter the holder openings through the duct opening 121.
  • the vacuum which is drawn in the partially opened damper position 114" shown in FIGURE 3 is about 10% in centimeters of mercury of the vacuum which is drawn with the damper in its position indicated by 114' where the duct opening is closed.
  • the cylinder 116 is supplied pressurized fluid to extend its piston rod 119 in order to locate the damper 114 in its solid line indicated position so that the vacuum drawn at the lower holder surface 94 is terminated in order to let the glass drop under the force of gravity.
  • vacuum holder 92 is supported below the housing roof 47 by vertical rods 122 whose lower ends are threaded to receive nuts 123. Holes 124 in the roof 47 receive intermediate portions of the rods 122 to allow vertical movement thereof and upper ends of the rods are interconnected by a bar 126 and secured to cables 128 of a support or pulley system 130. Brackets 132 rotatably support pulleys 134 of this system on the horizontal beam 52 shown in both FIGURES 8a and 8b and the cables 128 are trained over these pulleys.
  • a common plate 136 of a cylinder actuator 138 is connected to the cables 128.
  • Actuator 138 includes a cylinder 140 mounted on the vertical beam 54 and having a piston connecting rod 142 connected to the plate 136 by a pin 144.
  • Guide 146 is mounted by a bracket on the vertical beam 54 and guides the rod 142 during upward and downward extending movement by the cylinder 140 upon being supplied a suitable pressurized fluid. Upward movement of the rod 142 allows the cables 128 to lower the holder 92 shown in FIGURE 8b toward the conveyor rolls 68 in order to facilitate pickup of the glass by a vacuum supplied in the manner previously discussed. After the pickup, the vacuum holder 92 is raised by downward movement of the rod 142 shown in FIGURE 8a so as to move the supported sheet of glass on the holder upwardly away from the conveyor.
  • Auxiliary lifters 148 shown in FIGURE 11 are positioned between the conveyor rolls 68 and provide another mode of operation for facilitating the vacuum sheet glass pickup by the holder 92.
  • Auxiliary lifters 148 have T-shaped cross sections and extend parallel to the conveyor rolls 68 and transversely with respect to the direction of sheet glass conveyance within the furnace. Opposite ends of the lifters 148 extend outwardly through the furnace housing side slots and are supported by elongated bars 150 at the sides of the furnace, these bars being notched to receive the lower ends of the lifters.
  • a pair of cylinders 152 mounted on the vertical beams 36 as shown in FIGURE 8b have connecting rods 154 with upper ends connected to the bar 150 by pins 155 seen by reference back to FIGURE 11.
  • Pressurized fluid is supplied to cylinders 152 in order to extend their rods 154 and raise the associated bar 150 as well as the auxiliary lifters 148 from the solid line indicated position of FIGURE 11 to its phantom line indicated position in order to lift the heated sheet of glass upwardly toward the vacuum holder 92.
  • This upward movement of the glass positions it in proximity to the lower surface 94 of the vacuum holder so as to facilitate the glass pickup.
  • cylinders 152 are supplied pressurized fluid to retract their piston connecting rods 154 so as to lower the auxiliary lifters 148 back between the conveyor rolls 68.
  • spaced rails 156 of the quench unit 24 mount a pair of carriers 158 and 160 for movement perpendicular to the direction of glass conveyance within the furnace.
  • Carrier 158 includes crossing straps 162 (FIGURE 10) on which a mold in the form of a ring 164 (hereinafter more fully described) is supported for movement between the furnace 22 and the quench unit 24.
  • Carrier 160 likewise includes crossing straps 166 on which a delivery ring 168 is supported for movement between the quench unit and an operator who stands adjacent the apparatus at the left-hand side of FIGURE 8a.
  • Carrier 158 extends into the furnace heating chamber in a cantilevered manner upon movement to the right to position ring 164 below the vacuum holder 92. In this position, the carrier extends through the housing side slot 70 at the adjacent side of the furnace. Movement of the carrier 158 to the left pulls the ring 164 out of the furnace through this side slot 70 and moves it into the quench unit 24.
  • carrier 158 shown in FIGURE 10 moves the mold ring 164 beneath the vacuum holder 92 with a heated sheet of glass supported on its lower planar surface 94. Vacuum supplied to the holder 92 is then terminated so that the heated glass drops down onto the mold ring 164 within the furnace heating chamber 50.
  • a helical spring 170 see FIGURES 4-6, is wrapped about mold ring 164 in a helical shape and engages the periphery of the glass with point contact so as to minimize any cooling effect that the ring will have on the glass. Due to its heated condition, the planar sheet of glass begins to sag under the bias of gravity so as to assume the curved shape of the ring as seen in FIGURE 5.
  • Carrier 158 continues to position the mold ring 164 within the heating chamber for a momentary dwell period so that the glass sags a sufficient extent without oversagging, this period of time depending upon the particular configuration to which the glass is to be bent. After this dwell within the furnace, normally for one to ten seconds, the carrier 158 moves from the furnace heating chamber 50 shown in FIGURE 8b to the quench unit 24 shown in FIGURE 8a and positions the bent sheet of glass between lower and upper blastheads 172 and 174 of the quench unit. Each of these blastheads is preferably of the type disclosed in United States Patent 3,936,291, the entire disclosure of which is hereby incorporated by reference.
  • a blower 176 shown in FIGURES 3 and 9 supplies a duct 178 with air that acts as a cooling fluid.
  • Branch ducts 180 and 182 from duct 178 respectively feed the lower and upper blastheads 172 and 174 so that the air is sprayed from the blastheads through nozzles thereof onto the opposite surfaces of the bent glass carried by the mold ring 164.
  • This air supply rapidly cools the glass surfaces to temper the glass and thereby increases its mechanical strength as well as causing the glass to break into small dull pieces.
  • Carrier 158 preferably oscillates back and forth between the blastheads to uniformly distribute the impingement of cooling air with the glass.
  • a control in the form of a cylinder 184 is then supplied pressurized fluid to extend its piston connecting rod 186 and to move the damper 188 of duct 182 from the solid line position to the phantom line position shown in FIGURE 3.
  • This damper movement closes the branch 182 to the air flow from the blower 176 and diverts the air supply from the upper blasthead 172 through the duct 180.
  • the cylinder 184 of FIGURE 3 is supplied a pressurized fluid to retract its rod 186 and pivot the damper 188 from its phantom line closed position to its solid line open position. Air from the blower 176 is then again supplied to the upper blasthead 174 as well as to the lower blasthead 172 so that the lifted sheet of glass drops down onto the delivery ring.
  • the carrier 160 moves the delivery ring to the left side of the apparatus as viewed in FIGURE 8a where a waiting operator can pick the glass off of the ring.
  • Delivery ring 168 thus functions as a delivery conveyor for the tempered glass. Suitable after-cooling blastheads may follow the quench blastheads and thereafter cool the glass to room temperature before conveyance to the operator.
  • actuators for moving the carriers 1 58 and 160 are embodied as continuous drive chains 192 and 194, respectively.
  • Drive chains 192 are located at the opposite sides of the quench unit and secured by connectors 196 to the carrier 158.
  • Chain sprockets 198 and 200 have the chains 192 trained over them with the sprockets 198 interconnected by a hollow cross-shaft sleeve 202 that couples the chains 192 for operation with each other.
  • chains 194 are secured to the carrier 160 by connectors 204 and are trained over sprockets 206 and 208 which are respectively aligned with the sprockets 198 and 200.
  • a cross shaft 209 extends through sleeve 202 and interconnects the sprockets 206 with each other.
  • Drive chains 210 and 211 shown in FIGURE 10 drive respective sprockets 212 and 213 from digital drives such as the electric stepper motors 214 and 215 in order to move the carriers 158 and 160 by the actuator chains 192 and 194 independently of each other.
  • Stepper motor 214 provides rapid movement of the carrier 160 on which the mold ring 164 is thereby moved from the furnace into the quench unit without significant heat loss. Accurate control of the acceleration and deceleration involved is also possible with the stepper motor drive of the carrier ring to prevent the glass from being marred by sliding on the ring as it starts and stops.
  • locating the quench unit 24 laterally with respect to the direction of glass conveyance through the furnace 22 from its end 26 to end 28 allows the glass to also pass straight out the furnace end 28 through a door opening 216 (FIGURE 9) where a quench unit for tempering planar sheet glass can be located.
  • another quench unit can also be located on the opposite side of the furnace end 28 shown in FIGURE 2 from the quench unit 24 so that glass sheets can be received from the furnace and transferred to the quench units on both sides of the furnace for tempering after first being bent in order to increase production output.
  • Planar surface 94 of the vacuum holder may have its center slightly raised with respect to its periphery, i.e. about one quarter of an inch higher on a surface of a 4 foot dimension so that the surface is not completely planar although it is generally planar. Such a slightly concave downward but generally planar surface reversely bends the glass prior to the bending on the ring to prevent overbending under the force of gravity.
  • Locator 218 includes a pair of cylinders 222a and 222b which have associated piston connecting rods 224a and 224b that extend into the housing of furnace 22 through the side slots from which the conveyor rolls 68 project outwardly to be driven by the continuous drive loops 74.
  • a first photoelectric sensor 225 coupled to panel 216 by a line 225' senses the glass to thereby actuate locator cylinders 222a and b so as to extend their piston connecting rods 224a and b.
  • Engagement of the rods with the sheets of glass G properly locates the glass at the correct lateral location on the rolls with respect to the vacuum holder in the proper angular orientation. Any improper angularity or lateral positioning of the sheets of glass G on the rolls is thus corrected by this locator 218.
  • the glass sheets G are triangular in shape as shown, being designed as control vent windows for vehicles. Two sensors are necessary since the location of the leading glass edge can change as the glass slides along the rolls during operation of the locator 218.
  • the exact position of the sheet glass with respect to the vacuum holder 92 is known at all times since the electric motor 88 of drive mechanism 86 is coupled by a line 230 to a counter 231 of the control panel 216 as is the sensor 226 by line 228.
  • Control lines 232 and 234 connect the vacuum holder cylinder actuator 140 and the auxiliary lifter cylinder actuators 152, respectively, to the control panel 216 and counter 231 thereof so that operation of these components is coupled with the sensing of the glass position by counting each motor revolution. Glass can thus be picked up off of the conveyor without first stopping its movement while always properly locating the glass longitudinally along the direction of conveyance with respect to the mold ring 164 that has a corresponding triangular shape with a required curvature for bending of the glass.
  • the chain actuators 192 and 194 for moving the mold and delivery rings 164 and 168 are also coupled by lines 236 and 238 to the control panel 216 in order to coordinate the movement of the sheet glass to the quench unit 24 from the furnace 22 and from the quench unit to the operator.
  • FIGURE 13 is a schematic view similar to a portion of FIGURE 12 of another embodiment of the apparatus.
  • Mold ring 164 is moved by its stepper motor driven chain actuator 192 from the furnace end 28 to and through the quench unit 24 in this embodiment. There is no transfer of the glass to another delivery ring by diverting air flow to the lower blasthead from the upper blasthead as with the previous embodiment of FIGURES 1-12. After removal . of the glass from ring 164 by the operator, the ring is driven back to the furnace ready to begin another cycle.
  • the mold ring 164 is preferably reciprocated by its carrier drive within the quench unit 24 to distribute the flow of air sprayed onto the glass. This distribution provides uniformity to the tempering of the glass.
  • FIGURE 14 A modified version of the apparatus is shown in FIGURE 14 and indicated by 20'. Except as will be noted, many of the components of this modified apparatus are the same as the previously described apparatus and as such bear like reference numerals.
  • the locator 218 is located adjacent the vacuum holder 92 rather than upstream from the single sensor 226.
  • the longitudinal position of the sheet of glass G is sensed by sensor 226 to control operation of the vacuum holder 92.
  • cylinders 152 raise the bars 150 and the auxiliary lifters 148
  • the sheet of glass G supported on the auxiliary lifters is engaged by extension of the rods 224a and b of the locator cylinders 222a and b and slid along the auxiliary lifters to the proper angular orientation and lateral position.
  • Control panel 216 and its counter 231 coupled to the electric motor 88, the vacuum holder cylinders 140 and 152, the locator 218, and the sensor 226 provide sequenced operation of the apparatus.
  • Auxiliary lifters 148 each have the T shape shown in FIGURE 15 and include an upper crossbar 236 and a lower stem 238 that projects downwardly from the crossbar.
  • This T shape provides a rigid auxiliary lifter that can be positioned between the conveyor rolls 68, even when the rolls are closely spaced, and nevertheless function as required.
  • Crossbar 236 can have a width greater than the spacing between the rolls 68 and still be located below the upper sides of the rolls in the lower position so that the glass G can be conveyed on the rolls prior to being picked up as shown by the phantom line indicated position.
  • a modified embodiment 92' of the vacuum holder is shown as having a downwardly facing surface 94' which is of a curved shape.
  • a heated sheet of glass is conveyed under the vacuum holder 92' by the conveyor 66 and then lifted upwardly by the auxiliary lifters 148 which move from the solid line position of FIGURE 16 to the phantom line position thereof to engage the sheet of glass G as shown against the curved surface 94'.
  • Ends of the auxiliary lifters 148 are supported by a suitable power- operated actuator which is capable of lifting auxiliary lifters at the left and right extremes a greater distance than the ones in the center to conform the sheet of glass with the downwardly convexed shape of the curved surface on the vacuum holder.
  • a vacuum drawn within the holder 92' then supports the sheet of glass against the surface 94' and the auxiliary lifters 148 are moved downwardly.
  • Carrier 158 then moves the mold ring 164' beneath the holder 92' and the vacuum being drawn is terminated so that the sheet of glass G drops onto the mold ring.
  • the mold ring 164' has a greater curvature than the vacuum holder surface 94'. Further bending of the sheet of glass G thus takes place on the mold ring 164' under the bias of gravity.
  • Carrier 158 then moves the mold ring 164' from below the vacuum holder 92' out of the furnace heating chamber and into the quench unit in the same manner previously described.
  • Relatively deep bends can be made by the prebending on the holder surface and the subsequent gravity bending on the ring as described in connection with FIGURES 16 and 17.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)
EP79300012A 1978-01-25 1979-01-04 Apparatus for bending and tempering glass Expired EP0003391B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US87220178A 1978-01-25 1978-01-25
US872201 1978-01-25

Publications (2)

Publication Number Publication Date
EP0003391A1 EP0003391A1 (en) 1979-08-08
EP0003391B1 true EP0003391B1 (en) 1983-05-25

Family

ID=25359051

Family Applications (1)

Application Number Title Priority Date Filing Date
EP79300012A Expired EP0003391B1 (en) 1978-01-25 1979-01-04 Apparatus for bending and tempering glass

Country Status (10)

Country Link
EP (1) EP0003391B1 (enrdf_load_stackoverflow)
JP (1) JPS54110217A (enrdf_load_stackoverflow)
AU (1) AU523213B2 (enrdf_load_stackoverflow)
BR (1) BR7900437A (enrdf_load_stackoverflow)
CA (1) CA1120725A (enrdf_load_stackoverflow)
DE (1) DE2965480D1 (enrdf_load_stackoverflow)
FI (1) FI790218A7 (enrdf_load_stackoverflow)
IN (1) IN150716B (enrdf_load_stackoverflow)
MX (1) MX151961A (enrdf_load_stackoverflow)
ZA (1) ZA7939B (enrdf_load_stackoverflow)

Cited By (1)

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DE4034600C1 (enrdf_load_stackoverflow) * 1990-10-31 1992-02-20 Vegla Vereinigte Glaswerke Gmbh, 5100 Aachen, De

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JPS5571634A (en) * 1978-11-13 1980-05-29 Ppg Industries Inc Method of forming glass plate
CA1128755A (en) * 1978-11-13 1982-08-03 Ppg Industries, Inc. Method and apparatus for shaping glass sheets by drop forming
US4252552A (en) * 1979-09-25 1981-02-24 Ppg Industries, Inc. Shaping glass sheets using molds of different shapes
US4360374A (en) * 1980-11-24 1982-11-23 Nitschke John Stephen Roll operator for glass sheet conveyor of bending system
US4364766A (en) * 1981-05-01 1982-12-21 Nitschke John Stephen Control system for monitoring and controlling the processing of glass sheets in a glass processing environment
DE3238043C1 (de) * 1982-10-14 1983-09-29 Flachglas AG, 8510 Fürth Vorrichtung zum Vorspannen einer Glasscheibe
CA1199794A (en) * 1983-05-24 1986-01-28 Ppg Industries Ohio, Inc. Arrangement of apertures for vacuum holders for shaping glass sheets
US4517001A (en) * 1984-03-19 1985-05-14 Glasstech, Inc. Apparatus for bending glass sheets
US4578103A (en) * 1984-11-23 1986-03-25 Glasstech, Inc. Glass sheet processing system including topside transfer apparatus
DE3517835C1 (de) * 1985-05-17 1986-12-18 Ver Glaswerke Gmbh Verfahren und Vorrichtung zum Biegen und Vorspannen einer Glasscheibe in horizontaler Lage auf einer Umfangbiegeform
FR2587309A1 (fr) * 1985-09-18 1987-03-20 Saint Gobain Vitrage Dispositif de prehension et de transfert des feuilles de verre apres leur trempe thermique.
FR2596750B1 (fr) * 1986-04-03 1988-06-03 Saint Gobain Vitrage Dispositif de formage du verre
FR2596751B1 (fr) * 1986-04-08 1988-06-03 Saint Gobain Vitrage Dispositif de formage du verre
FR2606383B1 (fr) * 1986-11-06 1989-01-13 Saint Gobain Vitrage Positionnement de plaques de verre en vue notamment de leur bombage
DE3640892A1 (de) * 1986-11-29 1988-06-09 Ver Glaswerke Gmbh Verfahren und vorrichtung zum biegen einer glasscheibe
DE3721863A1 (de) * 1987-07-02 1989-01-12 Ver Glaswerke Gmbh Haltevorrichtung mit saugwirkung fuer glasscheiben und verwendung der haltevorrichtung bei einem verfahren zum biegen von glasscheiben
FR2644776B1 (fr) * 1989-03-24 1991-05-31 Saint Gobain Vitrage Positionnement d'une feuille de verre par rapport a des outils de bombage et/ou d'autres traitements thermiques
DE3913571C1 (enrdf_load_stackoverflow) * 1989-04-25 1990-07-26 Vegla Vereinigte Glaswerke Gmbh, 5100 Aachen, De
DE3929042C1 (enrdf_load_stackoverflow) * 1989-09-01 1991-01-10 Vegla Vereinigte Glaswerke Gmbh, 5100 Aachen, De
FR2677015B1 (fr) * 1991-05-30 1993-08-13 Saint Gobain Vitrage Int Revetement pour moules annulaires de bombage/trempe.
JPH0660673U (ja) * 1993-02-02 1994-08-23 株式会社イナックス 給水装置
DE4334213A1 (de) * 1993-10-07 1995-04-13 Ver Glaswerke Gmbh Verfahren und Vorrichtung zum Biegen von Glasscheiben
JP2007040699A (ja) * 2006-08-08 2007-02-15 Koyo Thermo System Kk ローラハース式連続焼成炉

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US3455672A (en) * 1966-11-28 1969-07-15 Ppg Industries Inc Apparatus for shaping and tempering glass sheets with means to transport the sheets therebetween
US3607187A (en) * 1969-01-08 1971-09-21 Permaglass Method and apparatus for reshaping glass sheets
FR2085464B1 (enrdf_load_stackoverflow) * 1970-04-23 1974-08-09 Saint Gobain Pont A Mousson
US3684473A (en) * 1970-08-28 1972-08-15 Libbey Owens Ford Co Bending and tempering glass sheets
ZA738969B (en) * 1973-01-10 1975-06-25 Ppg Industries Inc Handling glass sheets for shaping and cooling
US3862828A (en) * 1973-10-19 1975-01-28 Libbey Owens Ford Co Controlling glass sheet furnace & temperatures
US3951634A (en) * 1974-06-20 1976-04-20 Libbey-Owens-Ford Company Method of and apparatus for bending and tempering thin glass sheets

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Publication number Priority date Publication date Assignee Title
DE4034600C1 (enrdf_load_stackoverflow) * 1990-10-31 1992-02-20 Vegla Vereinigte Glaswerke Gmbh, 5100 Aachen, De

Also Published As

Publication number Publication date
DE2965480D1 (en) 1983-07-07
AU523213B2 (en) 1982-07-15
CA1120725A (en) 1982-03-30
JPS6132264B2 (enrdf_load_stackoverflow) 1986-07-25
MX151961A (es) 1985-05-22
EP0003391A1 (en) 1979-08-08
FI790218A7 (fi) 1979-07-26
AU4313179A (en) 1979-08-02
ZA7939B (en) 1979-12-27
BR7900437A (pt) 1979-08-21
JPS54110217A (en) 1979-08-29
IN150716B (enrdf_load_stackoverflow) 1982-11-20

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